Re-emerges yellow fever infections: potential threat for global public health, present status, diagnosis, and future perspective – correspondence
Authors: Shopnil Akash, Md. Mominur Rahman, Farjana I. Aovi, Nurun N. Zaman
Journal: International Journal of Surgery (2023)

Dear Editor, The infectious hemorrhagic fever, known as yellow fever, is caused by a virus spread by mosquitoes. It has a high fatality rate. Migration of susceptible people to forested territories where the ailment is transmitted and rapid urbanization were considerations associated with yellow fever occurrences in South America1. An annual estimate of severe cases ranges from 84 000 to 170 000, and fatalities range from around 29 000 to 60 0002. During the 17th–19th centuries, an epidemic of yellow fever moved over the Atlantic to North America and Europe, where it disrupted businesses, slowed growth, and sometimes devastated people3. Other concerns that were attributed to the recurrence of the disease in South America included a relatively low vaccine coverage in areas where outbreaks of the disease occurred. According to certain findings, unvaccinated tourists were also functioning as a possible source of infection for yellow fever in other regions of the globe1. Yellow fever is a well-known illness that threatens public health in Africa, South and Central America, the Caribbean, and Mexico. However, the disease may also be found in the southern regions of the United States, and at this time, the illness is considered endemic to 31 countries in sub-Saharan Africa, where it is estimated that 508 million people are at risk, as well as 13 countries in Latin America, where it is estimated that 400 million people are in danger1,4. Recently, nine African nations, including Cameroon, Chad, Côte d'Ivoire, the Central African Republic, the Democratic Republic of the Congo, Gabon, Ghana, Nigeria, and the Republic of the Congo, reported 151 patients diagnosed with yellow fever in the year 2021. Six of these nine nations reported documented yellow fever cases in 2022, indicating that infection is still occurring, while Côte d'Ivoire and Nigeria have documented suspected cases, and Gabon has not confirmed any more instances since the year 2021. Kenya and Uganda are the newest nations to disclose suspected cases of yellow fever in the year 20225. In the period beginning on 1 January 2022 and ending on 26 August 2022, a total of 33 suspected cases of yellow fever were revealed from eight different African countries6. These countries included the Central African Republic (33%, 11 patients), Cameroon (24%, eight cases), the Democratic Republic of the Congo (13%), Kenya (9%), Chad (6%), the Republic of the Congo (6%), Uganda (6%), and Ghana (3%)7. From the beginning of 2021 until the end of 2022, a total of 274 patients with yellow fever were noted in Cameroon, the Central African Republic, Chad, Côte d'Ivoire, the Democratic Republic of the Congo, Ghana, Kenya, Niger, and the Republic of the Congo. During this period, the Republic of the Congo also experienced an outbreak of yellow fever. Around one-third of all substantiated cases were identified by Ghana during the last 3 months of 2021, making it the time during which the bulk of cases were discovered to have been recorded. Seventy-three percent of the verified cases include people younger than 30 years old, and the male-to-female ratio is 1 : 26. The yellow fever diagnostic testing will examine the viral DNA and unique bond proteins known as antigens and immune system proteins known as antibodies. Samples may be used to confirm a diagnosis of yellow fever and for other microscopic examinations of the diseased body. Samples of the patient's blood or tissues are taken to examine the viral genetic material. Even in severe infections, the viral genome is only detected in extremely low quantities in the body; hence, a process known as PCR must be carried out to produce many copies of the viral RNA. Because PCR was designed to multiply DNA, RNA has to be amplified by a specific modification of the PCR reaction8. This process is called RNA amplification. After that, the RNA is put through a process known as electrophoresis, which allows for the separation of molecules according to their size and the electrical charge they carry so that they can be identified. This method helps differentiate between the many strains of the yellow fever virus. The immunohistochemistry method is used in other diagnostic tests to detect the viruses or antibodies. Immunohistochemistry refers to a chemical process that uses antibodies to identify the presence of disease-causing organisms. Both the enzyme-linked immunosorbent assay and the microsphere-based immunoassay are the tests that are used most frequently in the identification of the yellow fever virus. These two methods utilize antibodies glued to a membrane to isolate and detect specific types of proteins. The antibodies used in enzyme-linked immunosorbent assays and microsphere-based immunoassays are specific in that they bind to proteins associated with yellow fever and antibodies directed against the virus. In these tests, we seek something called immunoglobulin G, which is an antibody9. Other sorts of testing, called serological investigations, employ blood cells and immune system components called complements to identify virus proteins or antibodies. All types of inspections contain components that determine if antibodies or viral proteins are bound to the substances being examined. In addition, histological examination is used in diagnosing the yellow disease because clinical testing for yellow fever might take a few days, so the condition can worsen before the findings are verified3. There is currently no cure for yellow fever. So, it is so essential to take preventive steps like being vaccinated. The focus of the therapeutic exercise is to alleviate the symptoms, which consist of things like getting enough rest and drinks, as well as taking medication to ease things like discomfort and fever. Besides, this infection could be managed in several ways. This included, An Integrated Mosquito Management program is vital for minimizing mosquito bites and the spread of significant vector-borne illnesses. This is especially true concerning the control of Aedes aegypti, which may cause yellow fever. The vector-borne disease control initiative suggests using a four-pronged strategy that targets all stages of the mosquito's life cycle as part of a successful Integrated Mosquito Management campaign. We depend on a well-informed public to have an effective mosquito control program since mosquito control personnel can only accomplish so much, and there is a limit to what they can achieve10. Ethical approval Not applicable. Sources of funding Not applicable. Author contribution S.A.: conceptualization. S.A. and M.R.: writing and original draft preparation. S.A., F.I.A., and N.N.Z.: writing and editing. M.R.: supervision. All authors have reviewed and approved the final version of the manuscript before submission. Conflicts of interest disclosure The authors declare no conflict of interest, financial, or otherwise. Research registration unique identifying number (UIN) 1. Name of the registry: not required. 2. Unique identifying number or registration ID: not required. 3. Hyperlink to your specific registration (must be publicly accessible and will be checked): not required. Guarantor Md. Mominur Rahman (corresponding author) is taking full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish. Data availability statement All data are available within the manuscript.